Granite

Tarn Granit

Tarn Granit is a classic European dimension stone from the Sidobre massif east of Castres in the French Tarn département (Occitanie) – a Hercynian two-mica granite with a characteristic salt-and-pepper grain fabric of white feldspar, dark biotite and mica crystals as well as a pale quartz content. For centuries the Sidobre deposit has been regarded as France's “granite capital”. At ROSSITTIS we fabricate Tarn Granit into exterior and interior floors, stairs, skirtings, window sills, façade elements, headstones and made-to-measure workpieces with a classic, timeless European dimension stone character.

Granite France 2.700 kg/m³

Available as: Slabs, Skirting, Tiles and flooring slabs · 2 of 48 reserved

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About Tarn Granit

Background. Tarn Granit (also “Granit du Sidobre” or “Sidobre Granit”) is among the most tradition-rich European dimension stones. The deposits lie in the Sidobre massif east of Castres in the French Tarn département in the Occitanie region – on the western edge of the Cévennes, in a granite landscape regarded as France's largest granite quarrying area. Lacrouzette has been the centre of the local stone industry since the nineteenth century and carries the self-chosen title “Capitale Mondiale du Granit” (world capital of granite). More than a hundred active quarries shape the landscape and supply the European dimension stone market with kerbs, skirtings, stair treads, façade panels and headstones in French granite.

Geology. Petrographically, Tarn Granit is a Hercynian metamorphosed two-mica granite (French “granite à deux micas”) from the Carboniferous, deposited as a plutonic igneous rock some 305 to 320 million years ago and tectonically stressed in several phases since. Its mineralogy comprises plagioclase and orthoclase (white to transparent feldspars, the main share at around 60 %), quartz (pale grey and glassy, approx. 25 %) as well as biotite (black and micaceous) and muscovite (silvery and micaceous) as the two micas that give it its name. The grain size is medium, in the range of 3–10 mm – every individual crystal is clearly recognisable to the naked eye.

Appearance. The polished slab shows a classic salt-and-pepper picture with a marked black-and-white contrast: white to light grey feldspar and quartz crystals form the main share, and between them are distributed powerful deep black biotite clusters and individual silvery gleaming muscovite crystals. From a medium distance the surface looks grey-mottled; close up one discovers the clearly differentiated mineral fabric. Isolated pale brownish spots (oxidised biotite or small iron mineral inclusions) can occur – they are a mark of authenticity and not a defect.

Technical values. Tarn Granit is a technically very strong dimension stone. Bulk density is around 2,700 kg/m³, water absorption about 0.34 %, compressive strength 171 MPa and flexural strength around 16 MPa. Mohs hardness 6–7 (the quartz and feldspar components dominate). Frost resistance is clearly declared in the data sheet, and acid resistance (for normal domestic and building applications) is given. The polish is also durable outdoors – an important advantage over marbles and limestones, whose polish goes matt under weathering.

ROSSITTIS range. The surface finishes available from stock are listed in the »Finishes« block further down. From these we produce exterior floors (paving, squares, pool surrounds), interior floors, stairs with treads and risers, window sills, skirtings, façade elements, headstones and made-to-measure workpieces. The surface finishes available from stock are listed in the »Finishes« block further down. The polished version is the first choice for interior applications wanting a classically elegant European dimension stone character.

Application. Tarn Granit has been an established dimension stone for high-quality public projects for decades (squares, promenades, station forecourts, administrative buildings) and for private builds (entrance areas, stairs, façades, pool surrounds). In sacred architecture and cemetery work it is one of the most widely fabricated European granites for headstones. In the interior fit-out of classic and modern premium architecture it is a proven choice as well, above all where a calm, technical and long-lived dimension stone effect is wanted.

Comparison. Within the grey granite spectrum, Tarn Granit is one of the European classics and is frequently compared with the Chinese Padang G603/G623 (markedly more industrial, more neutral) and northern Italian Sardo Beta grades (somewhat warmer grey-brown). Tarn is usually more even in its grain fabric and with a clearly defined black-and-white contrast. Against other French granites (Brittany, Limousin), the Sidobre version is finer and cleaner in appearance. Against engineered quartz (Caesarstone), the natural stone stays livelier and more mineral, but quieter in its play of veining than a marble look.

An honest assessment. Tarn Granit is a choice for clients and architects looking for a classic, timeless European dimension stone with high technical resilience, a clear mineral material effect and long-lived usability outdoors. It is not a show stone and not an exotic – its strength lies in European dimension stone quality, calm and mineral dependability. For classic stairs, façades, exterior paving and monuments it is the first choice; in interior fit-out it works particularly well where the architectural language is restrained and material-conscious.

Technical data

Guide values for the stone type, taken from manufacturer and test reports. Natural stone is a natural product — individual batches and slabs can differ. For critical applications, request slab-specific test data.

Rohdichte 2.700 kg/m³

Druckfestigkeit 171,0 MPa

Biegezugfestigkeit 16,0 MPa

Wasseraufnahme 0,34 %

Säurebeständig Nein

Suitability by application

Finishes

Tarn Granit is available in a range of finishes. The finish affects appearance, feel and the care it needs.

Polished

Polishing is the most classic finish in the hard stone segment — a mirror-smooth, high-gloss surface with the highest possible colour intensity and maximum depth effect in the mineral structure. As an acid-resistant silicate stone, polished granite is easy to care for and the first choice for kitchen worktops, wall claddings and prestigious exposed surfaces.

Flamed + brushed once

The surface is roughened by heat and brushed once to smooth sharp-edged mineral residues and remove loose material. The feel is somewhat gentler than purely flamed, it remains slip-resistant, and the colour is less intense than polished. The standard choice for outdoor areas, terraces and heavily used floor areas.

Care & fabrication

Cleaning. Day to day, warm water, a soft cloth or a clean mop and a neutral to mildly alkaline pH stone cleaner are enough. Soapy granite care products and mild all-purpose cleaners without acid are suitable. Granite is considerably more acid-resistant than marble – brief contact with acid (wine, lemon) leaves no etch marks, because the main quartz and feldspar components are inert to acid. Even so: prolonged contact with strong acids can attack the mica constituents.

Do not use. Avoid concentrated acids (sulphuric, hydrochloric, nitric acid), cement and rust removers, highly concentrated industrial cleaners and chlorine-based bleaches – they can attack the mica components and occasional pyrite inclusions. Solvent-based products (acetone, thinners) are unproblematic in normal concentrations, but are better rinsed off thoroughly.

Impregnation. A silane-polysiloxane-based impregnation is advisable on interior worktops, exterior floor coverings, stairs and window sills. It reduces the take-up of water and grease, prevents pigments from penetrating the micropores and makes ongoing cleaning easier. First impregnation directly after installation, refreshed every three to five years.

Kitchen. Tarn Granit is well suited as a kitchen worktop – the high acid resistance and scratch resistance of granite tolerates everyday use better than marble. Hot pots are in principle tolerated, but trivets are still advisable as standard practice. Chopping boards make sense – not for the sake of the granite (which is harder than any knife), but to spare the knives.

Bathroom. Very well suited in the bathroom as a vanity top, wall cladding, bath surround and shower. Anti-limescale sprays and sanitary cleaners are unproblematic in normal use. The surface finishes available from stock are listed in the »Finishes« block further down.

Floors and stairs. The classic domain. The surface finishes available from stock are listed in the »Finishes« block further down. Dirt-trapping mats at the entrance considerably reduce the ingress of abrasive particles.

Outdoors. Fully suitable. Frost-resistant, acid-resistant against rain and normal environmental exposure, and the polish is durable outdoors. The surface finishes available from stock are listed in the »Finishes« block further down.

Repair. Deeper damage can be filled by a stonemason with tinted, polyester resin-based granite filler and worked in to an exact colour match. Refreshing the polish by hand or with a polishing steel is possible on large-area damage; for local scratches a professional polish by the stonemason is usually enough.

Frequently asked questions

What is Tarn Granit geologically?

It is a Hercynian consolidated two-mica granite (granite à deux micas) from the Carboniferous (about 305–320 million years old) from the Sidobre massif east of Castres in the French Tarn département (Occitanie region). Mineralogically it consists of plagioclase/orthoclase (feldspars, approx. 60 %), quartz (approx. 25 %) as well as biotite and muscovite as the two micas that give it its name. Grain size medium (3–10 mm).

Where does the name come from?

The name refers to the Tarn département in southern France (Occitanie), or more specifically to the Sidobre massif east of Castres with Lacrouzette as the centre of the stone industry. The region has been systematically quarried since the nineteenth century and is regarded as France's “Capitale Mondiale du Granit” (world capital of granite) with more than a hundred active quarries.

What exactly does Tarn Granit look like?

A classic salt-and-pepper picture with a marked black-and-white contrast: white to light grey feldspar and quartz crystals as the main share, with powerful deep black biotite clusters and individual silvery gleaming muscovite crystals between them. Grey-mottled from a distance, with a clearly differentiable mineral fabric close up.

Which technical values does Tarn Granit have?

Bulk density around 2,700 kg/m³, water absorption 0.34 %, compressive strength 171 MPa, flexural strength 16 MPa, Mohs hardness 6–7. Frost resistance is clearly declared, acid resistance is given (quartz/feldspar dominant), and the polish is durable outdoors.

Is Tarn Granit suitable for exterior use?

Yes – that is one of its core domains. Frost resistance is given, the polish lasts outdoors, and the flamed + brushed version offers high slip resistance. Classic exterior applications are floor coverings, pool surrounds, stairs, façade panels and headstones.

Which surface finishes does ROSSITTIS supply?

The surface finishes available from stock are listed in the »Finishes« block on this page.

Which cleaners may I use on Tarn Granit?

Permitted are warm water, neutral to mildly alkaline stone care products and mild all-purpose cleaners. Granite is considerably more acid-resistant than marble; brief contact with acid (wine, lemon, vinegar) is unproblematic. Off limits are concentrated industrial cleaners, highly concentrated acids and chlorine-based bleaches in high concentration.

Tarn Granit or Padang G603?

Padang G603 is the Chinese volume granite for exterior applications – cheaper, but more industrial in character and with a less pronounced salt-and-pepper picture. Tarn Granit has a European dimension stone character, a markedly clearer black-and-white mineral fabric and is traditionally regarded as the higher-quality choice for prestige projects.